I don't think that's been sociologically plausible for many decades. Some things are easy to tear down and nearly impossible to build back up. In some circles, the mere suggestion that this should be a policy goal is insulting, as it hints that single-parent homes are inferior. Our government isn't really allowed to prefer one over the other, even if it would result in less misery. Furthermore, the tools that governm…
Single parent households are inferior, so why not spell it out?
A single parent with a strong local community of caregivers who can help perform the work of raising a kid in their community is probably not worse off than the standard, alienated two parent household in America.
So while what you say might be true in America, I don't think it's axiomatic.